Questions about the classification of thermal resistors
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Hello, experts! I have a question that I still haven’t figured out, and it relates to the classification of thermal resistors. I’ve seen that thermal resistors are generally classified into assembled thermal resistors, armored thermal resistors, etc., but what exactly is an armored thermal resistor? As I understand it, an armored thermoresistor is one that has only a protective tube around the measuring element, without any outer shielding sleeve; moreover, the protective tube surrounding the measuring element should be no thicker than 8 mm and easy to bend – such is what constitutes an armored version. As long as there is an outer sheath on them (with a diameter of around 12, 14, 16 mm or larger), they should not be considered armored thermoresistors. But I’ve found that many manufacturers also refer to those thicker types with an outer shield as armored thermoresistors. I’m really confused… I’d like to ask everyone what exactly an armored thermoresistor is
Think of it this way: the original thermal resistor is just a very thin wire, around 6mm or 8mm in diameter; those with an armor coating are the armored types, while those with an additional sleeve on the outside are typically pre-assembled thermal resistors. So it’s fine to use armored thermoresistors in the assembly as well. But isn’t it the case that the diameter of such armored types is already very large? I’ve seen few actual examples of this~
Some factories now place armored thermoresistors inside protective sleeves to replace the original thermoresistor elements; this approach reduces costs, and the reliability is even higher than that of the original elements.
As I understand it, a prefabricated thermal resistor consists of the wires welded to the thermal resistor, which are then covered with ceramic rings or other heat-resistant insulating materials, and afterward inserted into a sleeve. . . With such thermal resistors, they get damaged after being used for a while; you can remove the damaged one and replace it with a new one. In other words, it’s possible to only replace the core element, without needing to change the outer tube. . . Obviously, this type of packaging has some minor weaknesses in terms of heat transfer speed, shock resistance, and oxidation resistance. As I understand it, an armored thermoresistor is one in which the thermoresistor itself and the wires welded to it are all tightly wrapped in heat-resistant insulating material and fixed inside a sleeve. . . The instantaneous resistance element, wires, insulating material, and casing form an inseparable whole. . . In this way, the thermal resistor gets damaged after being used for a while, and it can only be replaced as a whole together with its sleeve. . . Obviously, this type of packaging has some minor advantages in terms of heat transfer speed, shock resistance, and oxidation resistance.
Am I understanding correctly? I don’t know either