Elevator air lock

Abstract From the Canadian patent

An air lock or transition chamber for controlling air pressure during ingress and egress from a multi-story building the interior of which is at an elevated air pressure. An elevator car is provided with a substantially air-tight seal on its door. Persons entering the building pass through an entrance lobby or an underground garage and enter the elevator. These locations are an ambient atmospheric pressure. The elevator doors close and the elevator moves to the desired floor which is, at an elevated pressure. As the elevator car moves the pressure, within the elevator increases either substantially to the, elevated pressure of the destination or to a pressure between ambient atmospheric …