(under subclass 157) Devices in which there is a separate pipe associated with the screen for passing fluid downwardly into the well to wash the screen, the separate pipe being readily removable from association with the screen structure while the screen remains in the well.
(1) Note. Wash pipes which are disclosed as merely liftable from the screen structure (e.g., the back pressure valve) are classified in this subclass if they are also disclosed as
capable of being completely removed from the well leaving the screen in the well.
SEE OR SEARCH THIS CLASS, SUBCLASS:
143+, for devices as defined in this subclass in which the detachable jet or wash pipe is a central conduit and there is a packer carried by the screen.
