SOURCE OF VACUUM AND DEVICE FOR CREATING AND MAINTAINING ANEGATIVE PRESSURE IN AN ENCLOSURE

摘要

The source of vacuum comprises a tubular body in which a piston which is combined with a piston rod is axially slidable. A seal is interposed between the rod and the body where the rod extends out of the body. A suction orifice is provided which is on the axis of or in the vicinity of the axis of the body and parallel to the axis. An arrangement is provided for holding the body and urging the piston to one end of the body in one hand. A communication passage is provided for putting the suction orifice in communication with a chamber defined between the piston and the body when the piston is depressed relative to the body.