US PATENT SUBCLASS 417 / 58
.~ Having condition or position responsive control of motive fluid supply


Current as of: June, 1999
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417 /   HD   PUMPS

56  DF  DRILLED WELL FREE PISTON-TYPE PUMP {4}
58.~ Having condition or position responsive control of motive fluid supply


DEFINITION

Classification: 417/58

(under subclass 56) Apparatus in which there is provided valve means for controlling the inlet of motive fluid to the motor chamber, said valve means comprising mechanical elements which are relatively moved 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 positioned within the motive fluid supply line which opens in the direction of motive fluid supply to the motor chamber is not considered to be condition responsive control.

(2) Note. Supply of motive fluid which is controlled by well liquid level in which the well liquid serves to directly cover or uncover motor chamber supply ports is excluded under this definition. However, a piston controlled cylinder port which is subsequently opened to allow the supply additional motive fluid is included hereunder.