What is the freezing point of silicone oil inside a double-flange capillary? If heating is applied, will it vaporize and cause the diaphragm box to expand?

Check the instrument specification sheet, the requirements at the time of ordering, and the materials returned by the manufacturer

If I remember correctly, there are 2 types of silicone oils: one can withstand temperatures up to 200 degrees, and the other can handle around 350 degrees.

What’s the temperature with that kind of heating? Cutting the meat into pieces – it probably won’t get hot enough to cook properly even throughout the winter. Silicone oil doesn’t vaporize at all; it’s extremely stable, just as stable as the Party. . .

But the large temperature differences between day and night cause instability in the transmitter; isn’t it a problem with the silicone oil? Could it be that the circuit board inside the header is not heat-resistant?

The instability is not caused by a problem with the silicone oil; it is generally due to crystallization of the material at the flange (this is just a guess – I don’t know what kind of material is being used). Since the issue isn’t severe enough to cause malfunction, insulation and heating measures were applied to that area of the flange.

This can cause fluctuations in the measurements; when providing heat tracing, it’s best to keep the heat tracing tube separated from the pressure guide tube, without them being in close contact

1. The temperature difference between day and night is large, but it shouldn’t exceed 30°C, right? 2. In normal circumstances, even for the temperature coefficient of voltage transformers, it will never exceed 0.05% FS/°C, no matter how poor the quality is. Based on this worst-case criterion, a temperature change of 30°C results in a measurement error of at most 1.5% FS; moreover, this 1.5% change occurs gradually from midday to the depths of night, without any sudden fluctuations, thus showing no signs of instability. 3. The issue you mentioned of \"large temperature differences between day and night, resulting in unstable transmitters\" could be caused by the following reasons: ① The vacuum level during oil filling in the transmitter’s oil chamber is not up to standard. ②The temperature compensation of the transmitter is extremely poor – it’s as bad as anything. ③The temperature coefficient of the transmitter’s circuit board is too high (this possibility is considered to be extremely low; even the worst-quality circuit boards have a temperature coefficient of no more than 0.02% FS/°C, I guess)

It is said that there are a great many oil-filled remote transmitters that do not undergo temperature compensation; it is also said that some people simply don’t know how to carry out such compensation. As a result, they have large temperature errors and are affected by weather conditions, which is not surprising. .

For ordinary silicone oil, no heating is required; however, high-temperature silicone oil has specific requirements regarding the ambient temperature – it needs to be above 20 degrees to function properly

It depends on the type of silicone oil; different types vary. Usually, insulation and heat tracing are no problem. Some oils require an operating temperature above zero degrees