US PATENT SUBCLASS 137 / 511
.~ Direct response valves (i.e., check valve type)

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

455  DF  LINE CONDITION CHANGE RESPONSIVE VALVES {11}
511.~ Direct response valves (i.e., check valve type) {14}
512  DF  .~.~> Plural {6}
513.3  DF  .~.~> With leak passage {2}
514  DF  .~.~> With retarder or dashpot {2}
515  DF  .~.~> In couplings for coaxial conduits, e.g., drill pipe check valves {3}
516  DF  .~.~> With means for selecting area of valve or seat
516.11  DF  .~.~> Single head, plural ports in parallel {2}
516.25  DF  .~.~> Plural seating {1}
517  DF  .~.~> Biased open {3}
522  DF  .~.~> With external means for opposing bias {1}
524  DF  .~.~> With bias adjustment indicator
843  DF  .~.~> Resilient material valve {4}
526  DF  .~.~> Vacuum relief type
527  DF  .~.~> Pivoted valves {4}
528  DF  .~.~> Reciprocating valves {5}

DEFINITION

Classification: 137/511

(under subclass 455) Valves which are responsive to pressure of the line fluid on the face of the valve disc or plug itself.

(1) Note. Since they have no other actuator, their movement from a normal or neutral or biased position is caused solely

by change in the fluid flow or pressure in the line, and they return to their original position when the original condition is restored.

(2) Note. Mere check valves are included in this group of subclasses, but a system which is not primarily condition change responsive is not classified herein merely because it includes one or more check valves. Instead, it is placed in a subclass appropriate to the system claimed.

SEE OR SEARCH THIS CLASS, SUBCLASS:

508, for valves in which a tubular passage forming member moves in response to pressure of the line fluid and is biased closed, the tubular member having an exposed end comprising a separate reactor surface.

SEE OR SEARCH CLASS 222, Dispensing,

490, and 491+ for dispenser outlet elements operated by pressure of the contents.

251, Valves and Valve Actuation, appropriate subclasses for valves which have motor, mechanical, fluid pressure or manual means for opening or closing, but are biased to the other position by springs, weights, internal fluid pressure, etc., particularly. See (1) Note above. See also

336+, for biased valves, per se, and see the search notes to subclass 336.