US PATENT SUBCLASS 137 / 523
.~.~.~ With means for retaining external means in bias opposing position

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

455  DF  LINE CONDITION CHANGE RESPONSIVE VALVES {11}
511  DF  .~ Direct response valves (i.e., check valve type) {14}
522  DF  .~.~ With external means for opposing bias {1}
523.~.~.~ With means for retaining external means in bias opposing position

DEFINITION

Classification: 137/523

(under subclass 522) Valves provided with means for maintaining the bias relieving or valve opening means in the bias relieving or valve opening position.

SEE OR SEARCH CLASS

251, Valves and Valve Actuation,

89+, for valves with means for blocking or disabling the valve actuator, which means may hold the valve open, and see the search notes thereto.