airlock (arlok)

An air-tight chamber in a cai on in which operations are carried on under water, communicating by one door with the outer air and the main entrance-shaft of the cai on, and by another door with the chambers filled with condensed air in which the men are at work. Its purpose is to regulate the air-pre ure so that the change from ordinary air to condensed air may be made without injury. When a workman steps from the shaft into the air-lock the door of ingre is closed, and condensed air is admitted until the pre ure is the same as that in the working-chamber. The proce is reversed when leaving the cai on. by compre ed