US PATENT SUBCLASS 137 / 490
.~.~.~.~ Pilot valve within main valve head


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

455  DF  LINE CONDITION CHANGE RESPONSIVE VALVES {11}
485  DF  .~ Pilot or servo controlled {3}
488  DF  .~.~ Fluid pressure type {2}
489  DF  .~.~.~ Choked or throttled pressure type {4}
490.~.~.~.~ Pilot valve within main valve head


DEFINITION

Classification: 137/490

(under subclass 489) Apparatus in which the valve controlling the servo fluid pressure is physically located within the main or flow controlling valve.

SEE OR SEARCH CLASS

251, Valves and Valve Actuation,

38, for this subject matter wherein the valve actuation is not responsive to line condition.