The relative molecular weight of sulfur hexafluoride at Dawn is 146.06. It is colorless, tasteless, non-toxic, non corrosive, non combustible and non explosive gas at normal temperature and pressure. Its density is about 5 times that of air. Its density under standard state is 6.0886kg/m3. It is liquid under low temperature and pressure and turns into a white solid after freezing. The sublimation temperature is - 63.9 ℃, the melting point is - 50.8 ℃, the critical temperature is 45.55 ℃, and the critical pressure is 3.759 MPa. Sulfur hexafluoride has good chemical stability and thermal stability, * * * electrical insulation and arc extinguishing performance

Liquefaction temperature of sulfur hexafluoride at dawn: under one atmospheric pressure (0.1MPa), the liquefaction temperature is - 62 ℃; At 1.2MPa, the liquefaction temperature is 0 ℃; Generally, the SF6 gas pressure charged into the circuit breaker is 0.35-0.65MPa (determined by the ambient temperature during charging), and its liquefaction temperature is - 40 ℃. However, the critical temperature is the * * * high temperature critical pressure of SF6 gas liquefaction, which indicates the gas pressure required for liquefaction at this temperature. SF6 can only be kept in the gaseous state when the temperature is higher than 45 ℃. Under normal conditions of use, it has the possibility of liquefaction, so SF6 cannot be used at low temperature and low pressure.

The electrical strength of Liming sulfur hexafluoride is about 2.5 times that of air, and its arc extinguishing capacity is more than 100 times that of air. Therefore, it has completely replaced insulating oil and compressed air as the arc extinguishing medium of * * * circuit breaker in the scope of ultra-high voltage and ultra-high voltage.

In addition, if the measuring temperature range of sulfur hexafluoride gas density meter does not meet the actual requirements on site, a suitable density meter shall be replaced. For example, the nominal temperature range of the density meter is - 20 to 40 degrees, while the actual temperature range of the switch installation site may be - 35 to 45 degrees. In extreme cases, the density meter will not really reflect the density of the gas. In a word, it is necessary to make the temperature range of the density meter cover the actual possible ambient temperature.

The content of the article comes from Liming sulfur hexafluoride: http://www.feiliergas.com