There are a variety of factors that MIGHT affect accuracy of any measurement. Luckily, there is one factor that is guaranteed to always be present and that is the contribution of the standard that was used to verify the sensor. That is why traceability make a difference. Thanks again for these, Dietmar!
Dear Levent, thank you for asking this good question! The process fluid inside the pipeline will have just little difference between the middle of the pipeline and the inner wall. The heat dissipation within the metal thermowell is the reason for that temperature gradient inside the stem. The graph in the video is simplified and exaggerated to illustrate the physical phenomenon. The real gradient inside the process won't be very steep but it results in a measuring error anyway. Especially when dealing with short immersion lengths and barstock thermowells you should definitely take this into account during the planning phase of a measuring point. We hope that we have been able to help you.
There are a variety of factors that MIGHT affect accuracy of any measurement. Luckily, there is one factor that is guaranteed to always be present and that is the contribution of the standard that was used to verify the sensor. That is why traceability make a difference. Thanks again for these, Dietmar!
Dear Stephen, thank you for your comment. Your feedback is very appreciated!
Why is there a temp gradient inside the stem? It should be equal because it is wetted by process fluid.
Dear Levent, thank you for asking this good question!
The process fluid inside the pipeline will have just little difference between the middle of the pipeline and the inner wall. The heat dissipation within the metal thermowell is the reason for that temperature gradient inside the stem. The graph in the video is simplified and exaggerated to illustrate the physical phenomenon. The real gradient inside the process won't be very steep but it results in a measuring error anyway. Especially when dealing with short immersion lengths and barstock thermowells you should definitely take this into account during the planning phase of a measuring point.
We hope that we have been able to help you.
Geat sharing!