The role of the 'oil' in the oil filled pressure gauge

Some pressure gauge with oil, and some are not, what is the difference between this? Difference is that some, but not very big difference, but the difference between using occasions. In the pressure gauge & other; Oil & throughout; To what effect? Actually, the main purpose of the oil filled pressure gauges is to reduce the pointer in relatively large variations in pressure buffer to zero, to ensure that the purpose of the sensitivity of pressure gauge. This & other; Oil & throughout; If I can choose? The answer is definitely NO! This & other; Oil & throughout; Mainly glycerin and silicone oil. Two kinds of oil have different role, glycerin is mainly the seismic effect; Silicone oil can also have the effect of the seismic, silicone oil is more tolerance for low temperature than glycerol, however, if the outdoor temperature reached minus 20 ℃, glycerin is crystallized, but silicone oil can make the instrument work normally. So glycerol and silicone oil of these two kinds of oil can be used, but in the concrete choice at least when considering the two points: 1, the coefficient of thermal expansion, coefficient as small as possible, this mainly affected by temperature; 2, the use of occasions, the food industry both oil can't use, one thousand damage to diaphragm oil can contaminate food. Also do not recommend using measuring strong oxidizer, otherwise it will cause explosion. Finally, as a reminder, although you can ask the oil filled pressure gauge, but it must be carried out with the help of special equipment.