(under subclass 118) Devices in which there is a fluid passage through the packer connecting the space below the packer with the space above the packer, the passageway being controllable by a valve, closure or changeable restriction.
SEE OR SEARCH THIS CLASS, SUBCLASS:
126+, for devices as defined in this subclass in which the controllable passage through the packer is between a central chamber and the space below the packer.
129+, for devices as defined in this subclass in which the controllable passage is a bypass outside a central conduit.
