Abstract: The invention relates to methods of producing a vacuum in a recipient and vacuum pumps for effecting same.This method consists in the pressure within a recipient being lowered from the atmospheric pressure to an initial vacuum by preliminary evacuation of gases through a solid or liquid gas mass which congeals, when supercooled as a result of removal of its surface vapors, coincidental with the evacuation, the pressure being later brought to a high vacuum level. A baffle is placed in a vacuum pump chamber, dividing this chamber into two spaces, one connected to the recipient and the other to a preliminary evacuation system, wherein the baffle and one of the walls form a clearance, blocked by the liquid or solid gas mass. Such method and vacuum pump ensure production of a sterile oil-free vacuum from 760 mm Hg to 10.sup.-.sup.13 mm Hg and higher.