US PATENT SUBCLASS 137 / 421
.~.~.~.~ Weight or spring bias

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

386  DF  LIQUID LEVEL RESPONSIVE OR MAINTAINING SYSTEMS {11}
409  DF  .~ By float controlled valve {11}
416  DF  .~.~ Quick acting {4}
420  DF  .~.~.~ Trip mechanism {1}
421.~.~.~.~ Weight or spring bias

DEFINITION

Classification: 137/421

(under subclass 420) Apparatus which includes a weight or spring as the biasing means.

SEE OR SEARCH CLASS

251, Valves and Valve Actuation,

66+, for biased trip actuated valves, especially subclass 72 for weight biased trips, and see the search notes to subclass 66.