The oil filled pressure gauge is generally glycerin and silicone oil.
The effects of the two oils are not the same. Glycerin is mainly used for anti-vibration; silicone oil can also be used for anti-vibration, but silicone oil is more resistant to low temperatures than glycerin. If the outdoor temperature reaches minus 20 °C, glycerin will crystallize, But silicone oil can also make the meter work normally.
Both glycerin and silicone oil can be used, but at least two points must be considered when making specific choices:
1. Thermal expansion coefficient, the smaller the coefficient, the better, this is mainly affected by temperature.
2. When used, neither of these two oils can be used in the food industry. In case of diaphragm damage, the oil will contaminate the food. It is also not recommended to measure strong oxidants, otherwise it will cause an explosion.