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EJECTOR SYSTEMS INTRODUCTION
In many processes, VACUUM is a required condition for the operations involved. In some smaller applications, 'Vacuum Pumps' are used to fulfil the requirements.
Some distillation processes for example, are carried out under vacuum (at pressures below that of the atmosphere). The application of vacuum, decreases the boiling points of the liquids being separated, thereby reducing the amount of heat energy needed for the operation.
Atmospheric pressure, as we know, is expressed as 14.7 psia. However, in modern industry, the S.I. units of pressure in use are 'kilopascals' (kPa), where atmospheric pressure is expressed as 101,000 Pa (Pascals) or 101 kPa.
One Pascal is equal to One Newton per Square Meter : 1 Pa = 1 N/m^{2 }
Using the Imperial System, vacuum is generally measured in Inches of Mercury ( "Hg) or in Inches of Water ( "H2O ). In this system, Atmospheric pressure is equal to 30 "Hg. The Metric System ( S.I.) uses ' Millimetres of Mercury ' ( mmHg ), where atmospheric pressure is equal to 760 mmHg, or 1 atmosphere or about 1 bar.
