Vacuum generating apparatus including liquid ring pump, pre-separator, two heat exchangers and fine separator

摘要

A device for generating a vacuum comprises a liquid-ring vacuum pump driven by an electric motor and operating with a working fluid. A mixture of compressed air and working fluid from the pump flows to a preseparator which separates a major portion of the working fluid from the gaseous mixture. The separated working fluid is fed from a reservoir in the preseparator via a liquid cooling coil back to the liquid-ring vacuum pump, while the gas still loaded with a residue of the working fluid is fed to a fine separator by means of a gas cooler, working fluid separated in the fine separator being returned to the pump via a return line. The preseparator and the fine separator are physically spaced from one another. The gas cooler and the liquid cooling coil are also physically spaced from one another and are located in the path of the cooling air stream for the electric motor. The coolers are designed so that the gas from the preseparator is cooled to a substantially lower temperature than the temperature to which the working fluid is cooled in the liquid cooling coil.