[2025 Temperature Instruments] Calculation and Selection of Thermometer Tube Strength per ASME PTC 19.3 TW-2016
Thread Content
The attachment is: Calculation and selection of thermometer sleeve strength per ASME PTC 19.3 TW-2016.
The following reply is for reference only and is not part of the text. Under what operating conditions is it necessary to perform frequency calculations for thermometer casings: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=5493649&shareuid=172778
Calculation methods and software for the natural frequency, eddy current shedding frequency, and pressure resistance of thermowells: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=5501831&shareuid=172778
\"Practical Techniques for Temperature Measurement\": https://bbs.hcbbs.com/forum.php? ... amp;shareuid=172778
【Y2025】200 Questions on Temperature Meters: https://bbs.hcbbs.com/forum.php? ... amp;shareuid=172778
【2025 Temperature Meters】Can one thermocouple be connected to multiple display instruments or DCS system cards?: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=5696412&shareuid=172778
【2025 Temperature Meters】How to determine whether a temperature measurement system meets the technical requirements for process measurement: https://bbs.hcbbs.com/forum.php?mod=viewthread&tid=5696411&shareuid=172778
Even when thermocouples, thermal resistors, and bimetallic thermometers are of good quality, proper installation procedures are essential. To obtain as accurate measurement results as possible and minimize errors, it is crucial to pay attention to the depth at which these devices are inserted.
①For different measurement media, the insertion depth of the temperature sensor varies. To ensure measurement accuracy, the sensitive part of the temperature sensor must be fully inserted into the medium being measured. The required immersion length for temperature sensors is generally as follows: ◆ When measuring gases, thermocouples should have an immersion length of more than 95 mm, while thermal resistors and bimetallic thermometers should have an immersion length of more than 115 mm. ◆When measuring liquids, thermocouples, thermal resistors, and bimetallic thermometers should all be larger than 46 mm. ◆The total insertion depth of the temperature sensor is: temperature sensor mounting boss + wall thickness of the tube + immersion length.
②For different devices, the insertion depth of the temperature sensor varies due to differences in installation location. In design, we often use the centerline of the pipeline as a reference to determine the insertion depth of the temperature sensor. This method is suitable for most applications, but it may not be appropriate for temperature measurement in large-diameter pipes, tower equipment, furnaces, etc. Firstly, it could lead to waste; secondly, it makes it impossible to properly secure the sensor in place.
For temperature measurement in ordinary tower equipment, when the temperature sensor is installed horizontally, an insertion depth of 300–400 mm is sufficient. For temperature measurement in boiler furnaces, temperature sensors are usually installed horizontally; after accounting for the thickness of the refractory bricks in the furnace, the thermocouple only needs to be inserted 150 mm into the furnace.