What is the difference between oil-filled and non-oil-filled bimetal thermometers?

The difference between oil-filled and non-oil-filled bimetal thermometers is mainly in the difference between the two applications. Oil-filled bimetal thermometers are mainly used in places with environmental vibration, while non-oil-filled bimetallic thermometers, that is, ordinary bimetallic thermometers, are mainly used. Use in ordinary places.

What does the "oil" in the bimetal thermometers do?In fact, the main purpose of filling the bimetal thermometer with oil is to reduce the interference of the external vibration environment on the pointer and to ensure the sensitivity of the thermometer. Is this "oil" free to choose? The answer is definitely NO! This "oil" is mainly two kinds of glycerin and silicone oil. The functions of the two oils are also different. Glycerin mainly plays an anti-shock effect; silicone oil can also play a role in anti-shock, but silicone oil is more resistant to low temperature than glycerin. If the outdoor temperature reaches minus 20 ℃, the glycerin will crystallize. , but the silicone oil can also make the meter work properly.Therefore, both glycerin and silicone oil can be used, but at least two points must be considered when making a specific choice: 

1. Thermal expansion coefficient, the smaller the coefficient, the better, which is mainly affected by temperature;

2.Application occasions , Neither of these two oils can be used in the food industry. In case the diaphragm is damaged, the oil will contaminate the food. It is also not recommended in places where strong oxidants are measured, otherwise it will cause an explosion.