US PATENT SUBCLASS 417 / 57
.~ Having condition or position responsive control of pump discharge flow path


Current as of: June, 1999
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417 /   HD   PUMPS

56  DF  DRILLED WELL FREE PISTON-TYPE PUMP {4}
57.~ Having condition or position responsive control of pump discharge flow path


DEFINITION

Classification: 417/57

(under subclass 56) Apparatus in which there is provided means for controlling the flow of liquid from the pump chamber, said flow controlling means being operated in response to either (1) the sensing of a condition or change

in condition or (2) the arrival of the piston at a predetermined position in the cylinder.

(1) Note. For purposes of this definition, a mere check valve in the eduction flow conduit which opens in the direction of pump fluid eduction is not considered to be condition responsive control. Also, the mere passing of the eduction port by the free piston is not considered to be position responsive control of the type herein provided for.