US PATENT SUBCLASS 137 / 488
.~.~ Fluid pressure type

Current as of: June, 1999
Click HD for Main Headings
Click for All Classes

Internet Version by PATENTEC © 1999      Terms of Use


137 /   HD   FLUID HANDLING

455  DF  LINE CONDITION CHANGE RESPONSIVE VALVES {11}
485  DF  .~ Pilot or servo controlled {3}
488.~.~ Fluid pressure type {2}
489  DF  .~.~.~> Choked or throttled pressure type {4}
492  DF  .~.~.~> Single acting fluid servo {1}

DEFINITION

Classification: 137/488

(under subclass 485) Apparatus in which the means sensing a change in fluid condition controls the effectiveness of a fluid pressure which is employed for controlling the operation of the flow controlling valve.

(1) Note. The source of fluid pressure for operating the flow controlling valve may be external or may be the main flow line.

SEE OR SEARCH THIS CLASS, SUBCLASS:

105, for suction operated pilot controlled valves where the pilot valve is itself responsive to line suction. These are mainly milker pulsators.

SEE OR SEARCH CLASS

251, Valves and Valve Actuation,

25+, for fluid pressure servo type valve actuators which are operated by external means or do not include means sensing a change in fluid condition, and see the search notes to subclass 25.