(under subclass 227) Devices under the class definition comprising a screen combined with (1) a valve, closure or changeable restrictor as defined in subclass 224, (2) a destroyable portion or (3) a screen part removable from the well while the screen remains in the well.
SEE OR SEARCH THIS CLASS, SUBCLASS:
143+, for screens with packers and detachable setting means, there being a valve closure or changeable restriction between the conduit of the setting means and the space below the packer.
157+, for screens with washing point or shoes provided with valves.
181+, for screens with packers and detachable setting means.
231+, for spiral screens constructed so that the space between the spirals may be varied.
296, for processes for preventing flow into a strainer while it is being lowered by blocking the strainer openings. SEE OR SEARCH CLASS
137, Fluid Handling,
544+, for fluid handling means of general utility combined with screens.
210, Liquid Purification or Separation,
418+, for filters of general utility with flow controllers, and see the search notes thereunder.
