Why the color of the oil in the proof pressure gauge is changed ?

Generally, there are two kinds of filling oil filled in the pressure gauge, glycerin and silicone oil. The purpose of filling glycerin is to effectively reduce the vibration of the movement and spring tube of the pressure gauge and make the pressure gauge smooth and moderate the operation indication value, so as to effectively increase the service life of the pressure gauge.

There are several factors that affect the color of glycerin oil in the  pressure gauge

The quality of the oil is not good.

The cleaning process of the inner core (spring tube and copper head) of the oil filled pressure gauge after welding is not good. After the steel tube and copper base of the pressure gauge are welded by high temperature heating, a large amount of oxides and residual flux are generated and attached to the surface. If not cleaned, the oil filled pressure gauge will turn yellow in a short time

There is too high temperature effect in the use of oil filled pressure gauge, which destroys the internal components of glycerin, changes the physical properties of glycerin and turns yellow.