| 摘要 |
A process for the generation of a vacuum in a vessel comprises generating a vapour by heating a reservoir of a paraffin wax, discharging the vapour through an inlet into a gas entrainment zone connected to the vessel, thereby generating a vapour jet in the entrainment zone, allowing gas from the vessel to enter the vapour jet, allowing the vapour jet containing the gas to pass to a condensation zone, condensing vapour from the vapour jet in the condensation zone and separately recovering the condensed wax and the uncondensed material. Apparatus for the generation of a vacuum comprises a reservoir of a paraffin wax, heating means (15) to generate a vapour from the paraffin wax, a vapour conduit (16) providing a passage for the vapour, a pump vessel (1), which vessel (1) comprises a gas entrainment zone, a vapour inlet (8) connected to the vapour conduit (16) and of a form whereby vapour entering the pump vessel (1) is formed into a vapour jet (17) extending into the gas entrainment zone, a gas inlet (4) whereby gas entering the pump vessel is caused to contact the vapour jet (17), a vapour condensation zone arranged to receive the gas and vapour jet leaving the entrainment zone, cooling means (10) to condense vapour in the vapour condensation zone and means to recover separately from the condensation zone the condensed vapour and the gas. The paraffin wax is preferably a synthetic wax, in particular a wax prepared by a Fischer-Tropsch synthesis.
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