(under subclass 437) Apparatus comprising a single pump chamber having a plurality of inlet passages for pump fluid, each of said inlet passages being individually, cyclically controlled and either (1) supplied from different sources or (2) if supplied from a common source, the control means having different modes of operation or operating at different times in the pump cycle.
(1) Note. For purposes of this definition, cyclic control of the inlet passages is not limited to control which is effected during each stroke of a reciprocating pumping member
and includes control which is effected after a predetermined number of strokes of the pumping member.
(2) Note. A passage from which fluid is drawn from a portion of the pump assembly (e.g., bearing) for enhancing the function of said assembly portion (e.g., cooling, sealing) is not considered to be an inlet under this definition, this subject matter forming the basis of subclass 439.
(3) Note. A pump chamber having one inlet through a valve in a piston operating therein and another inlet through a valve not in the piston is intended to form subject matter under this definition, said valve being considered as having different modes of operation.
SEE OR SEARCH THIS CLASS, SUBCLASS:
242, for a cyclically controlled bypass between plural pump chambers which is in addition to the normal inlet flow paths to the chamber. 250+, for successive stage pumps having a pump fluid inlet intermediate of the pumping stages.
493+, for plural controlled inlet or outlet flow paths, the control of at least one of said flow paths being effected by a pumping member controlled port.
