New Technology for Remote Testing of Response Time of Installed Thermocouples.

摘要

A comprehensive research and development project was completed to provide newtechnology for remote testing of response time of thermocouples as installed in operating processes. A significant portion of this development depended on the Loop Current Step Response (LCSR) method. This method is based on heating the thermocouple internally by applying an electric current to its extension leads. The current produces Joule heating in the thermocouple and causes the thermocouple junction to settle several degrees above the ambient temperature. The current is then cut off and the thermocouple output is recorded as it cools to the ambient temperature. It has been established by experimental research and theoretical development carried out in this project that this cooling transient can be analyzed to provide the response time of the thermocouple under the conditions tested. With little additional effort, the equipment that was developed in this project can be adapted to provide a capability for in-situ assessment of static health, reliability, and accuracy of installed thermocouples.