Fluid serially moved to opposite side of pumping member:
(under subclass 437) Apparatus having a reciprocating pumping member and in which fluid is moved from one side of the pumping member to the opposite side thereof during one reciprocatory stroke direction and then moved in the direction of movement of the pumping member during the other reciprocatory stroke direction.
(1) Note. A piston having a cup shaped axially extending peripheral lip portion fabricated of flexible material and in direct contact with pump fluid which is radially movable relative to a cylinder sidewall responsive to pump chamber pressure to control fluid flow around the piston is not considered in itself to be a valve and, per se, does not form subject matter under this definition. However, such devices when claimed in combination with a valve for controlling fluid flow into or out of the pump chamber form subject matter under this definition.
SEE OR SEARCH THIS CLASS, SUBCLASS:
254+, for a successive stage pump comprising pumping chambers on opposite sides of a pumping member in which the fluid is serially pumped from one pumping chamber to the next.
545+, for a pump in which fluid is serially moved to opposite sides of a valved piston.
SEE OR SEARCH CLASS
92, Expansible Chamber Devices,
240+, for a piston having a sidewall portion including a peripheral axially extending flexible lip which may be disclosed as performing a valving function and see the search notes therein.
