How to measure the temperature of a self-flowing pipe that isn’t under control

Extend the length of the temperature electrode, or adjust its installation position; install it at the bottom, just make sure there are no omissions:lol

The situation described by the poster is indeed quite typical: there is dissatisfaction with the large fluctuations in liquid level in the self-priming pipeline. If sensors are installed on the side walls or at the top, it’s easy for them to fail to detect the liquid level when it is low. The suggestions in the replies to extend the electrode length or install it at the bottom are indeed valid approaches, but special care must be taken when installing it at the bottom – if the diameter increases from DN20 to DN100, eddies or deposits may form at the junction, and fluid may not always flow through the bottom of the gravity-fed pipe (for example, when the flow rate is low). It is recommended to consider installing it at the lowest point of the pipeline or at bends, taking advantage of the convergence of the fluid flow ； Use an insertion thermometer, making sure the probe reaches as far down as possible toward the center of the pipe, without touching the pipe walls ； If the liquid level fluctuates significantly, a guide tube or sleeve can be added to ensure that the probe remains submerged at all times. Furthermore, the measurement of uncontrolled free flow involves significant errors; it is best to use the signal from a level gauge for temperature compensation, or consider using non-contact temperature measurement methods (such as infrared) to see if they are suitable. It depends specifically on the medium and operating conditions; if possible, it is recommended to consult the instrument manufacturer or conduct a field simulation before deciding on a plan.