US PATENT SUBCLASS 251 / 44
.~.~.~.~ Differential reaction surface for line pressure

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

12  DF  FLUID ACTUATED OR RETARDED {12}
25  DF  .~ Pilot or servo type motor {8}
33  DF  .~.~ Choked pressure type servo motor {8}
43  DF  .~.~.~ Main valve biased open by line pressure {2}
44.~.~.~.~ Differential reaction surface for line pressure {1}
45  DF  .~.~.~.~.~> Diaphragm or bellows surface

DEFINITION

Classification: 251/44

(under subclass 43) Subject matter in which the constantly applied line pressure tending to open the main valve is applied to the inner side of a separate connected fluid reaction surface, such as a piston or diaphragm, of larger diameter than the valve and located adjacent thereto on the inlet side of the valve, this being the side to which it moves in opening, whereby the resultant opening force due to line pressure is determined by the differential area between the diameter of the reaction surface and the diameter of the valve seat.

(1) Note. The separate reaction surface may be the inner face of the upper end of a spool type element, the inner end surface of an inverted cup shaped valve element, an annular extension of the valve in the plane of its closing area, etc. In any case, the motion of the part of the valve which is in contact with the seat is against the flow.

(2) Note. This type of valve is sometimes called "inlet peripheral type", as distinguished from the "inlet central" type of subclasses 43 and 46.

SEE OR SEARCH CLASS

137, Fluid Handling,

494+, for line condition change responsive valves having

separate connected fluid reactor surfaces, especially subclass 509 for such valves seating in the direction of flow.