US PATENT SUBCLASS 137 / 515.3
.~.~.~ Valve seat threaded into a coupling element


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}
515  DF  .~.~ In couplings for coaxial conduits, e.g., drill pipe check valves {3}
515.3.~.~.~ Valve seat threaded into a coupling element


DEFINITION

Classification: 137/515.3

(under subclass 515) Devices in which a separate valve seat element is threaded into one of the coupling elements

(1) Note. The valve head may be carried by the removable seat element or may be attached elsewhere in the coupling.