What is the measurement unit of the vacuum freeze dryer?
Because J refers to the vacuum, it means that there is no space state of gas, but it is actually a vacuum environment that does not exist. Therefore, we generally say that the vacuum of a vacuum freeze dryer refers to a space of one D, and the atmospheric pressure is lower than the gas state, that is, the density of gas molecules in the space is lower than the density of gas molecules in the atmospheric pressure of the region.
Different vacuum states means that the space has different molecular number densities. For example, in the standard state (STP: 101 degrees Pa, 0,025 Pa), the molecular density of the gas is 2.6870*10/25m/-3, and the vacuum density is 1*. At 10/-4Pa, the molecular density of the gas is only 2.65*10/16m/-3.
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(2) Vacuum freeze dryer vacuum measurement unit
Vacuum is commonly used in vacuum freeze dryer technology to measure the extent of space gas under vacuum. Generally, the degree of vacuum is expressed by the pressure value of the gas, and the higher the pressure value, the lower the degree of vacuum; the lower the pressure value, the higher the degree of vacuum. Vacuum freeze dryer manufacturer
Commonly used pressure units are
(1) Pascal: the pressure unit in the country J unit, the legal pressure unit in China. 1Pa pressure is the force that acts 1N on an area of ​​1 square meter.
1Pa=1N/m2
Microbar: The pressure of 1 microbar is the force acting on 1d2 on an area of ​​1cm2.
1 microbar = 1dyn/cm2
Standard Atmospheric Pressure: At the 7th National J Measurement Conference in 1927, the standard atmospheric pressure was defined, that is, under the condition of gravity acceleration of 980.665 cm/s2, water Y temperature of 0 degree, and water Y density of 13.5915 g/cm3. The pressure generated by the 760mm high mercury column is called 1atm.
1atm=760mmHg=1013250dyn/cm2
The accuracy of this standard atmospheric pressure dependent mercury density measurement is not critical.
In 1954, at the Tenth National J Measurement Conference, the standard atmospheric pressure was redefined.
1atm=1013250dyn/cm2=101325Pa