US PATENT SUBCLASS 137 / 485
.~ Pilot or servo controlled

Current as of: June, 1999
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137 /   HD   FLUID HANDLING

455  DF  LINE CONDITION CHANGE RESPONSIVE VALVES {11}
485.~ Pilot or servo controlled {3}
486  DF  .~.~> Responsive to change in rate of fluid flow {1}
487.5  DF  .~.~> Electrically actuated valve
488  DF  .~.~> Fluid pressure type {2}

DEFINITION

Classification: 137/485

(under subclass 455) Apparatus within ... in which the means sensing a change in fluid condition within the apparatus controls the application of another source of power for operating the flow control valve rather than acting directly through a mechanical connection.

SEE OR SEARCH CLASS

251, Valves and Valve Actuation,

25+, for fluid servo-motors for nonautomatic valve operation, and see the search notes to subclass 25.