US PATENT SUBCLASS 251 / 48
.~ Dashpot or fluid controlled retarder or timer

Current as of: June, 1999
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251 /   HD   VALVES AND VALVE ACTUATION

12  DF  FLUID ACTUATED OR RETARDED {12}
48.~ Dashpot or fluid controlled retarder or timer {5}
49  DF  .~.~> Latch or trip releasing
50  DF  .~.~> Line pressure connected dashpot or choke chamber {2}
53  DF  .~.~> Line connected open accumulating chamber
54  DF  .~.~> Closed fluid circuit dashpot or choke chamber
55  DF  .~.~> With choke by-pass or relief means

DEFINITION

Classification: 251/48

(under subclass 12) Subject matter in which the valve is provided with a fluid reaction means that prescribes a rate of motion for, or an interval in, the operation of the valve.

SEE OR SEARCH THIS CLASS, SUBCLASS:

15+, for such devices in which the valve operating means is disconnected immediately after the operating force is applied or is overridden by the fluid reaction means, so that a predetermined flow is obtained before a compulsory cut-off.

36, and 47, for pilot or servo operated valves which have separate dashpots or choked fluid retarders.

64, for nonfluid timing or retarding means for valve actuators.

SEE OR SEARCH CLASS

16, Miscellaneous Hardware, 49+, for liquid checks and closers, subclasses 66+ for pneumatic checks and closers, and subclass 84 for pneumatic closure checks.

137, Fluid Handling,

469+, for pop type safety valves, i.e., those in which a separate reactor surface affected by the relieved fluid modifies the response of the valve to the line condition change after the valve opens and subclasses 514+ for dashpot controlled direct response valves.

188, Brakes,

297+, for a dashpot or shock absorber of general utility.

267, Spring Devices,

64.11+, for fluid pressure springs.