US PATENT SUBCLASS 166 / 146
.~.~ Passage connects with space below packers and continuously open passageway connects with space between packers

Current as of: June, 1999
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166 /   HD   WELLS

179  DF  PACKERS OR PLUGS {17}
142  DF  .~ With controllable passage between central chamber and space below packer {7}
146.~.~ Passage connects with space below packers and continuously open passageway connects with space between packers

DEFINITION

Classification: 166/146

(under subclass 142) Devices in which the passage connects with a space below a plurality of packer blocking means and there is a passageway which is always open to passage of fluid in either direction between the central conduit of receptacle and the annular space between the packer blocking means.