US PATENT SUBCLASS 417 / 244
SUCCESSIVE STAGES

Current as of: June, 1999
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417 /   HD   PUMPS

244SUCCESSIVE STAGES {8}
245  DF  .~> Fluid motor for one stage supplied from another stage
246  DF  .~> Stages driven by relatively movable motor working members {1}
248  DF  .~> Parallel stages to or from single stage
249  DF  .~> Prior stage delivers to atmospheric chamber
250  DF  .~> With interstage intake or additional inlet to latter stage
251  DF  .~> With interstage discharge or additional discharge from former stage {1}
253  DF  .~> Condition responsive control of fluid
254  DF  .~> Reciprocating rigid stages {8}

DEFINITION

Classification: 417/244

(under the class definition) Apparatus in which the pumped fluid is serially acted upon by a plurality of pumping units.

(1) Note. This definition includes those expansible chamber

pumps in which the fluid is pumped by being successively acted upon by opposed faces of a unitary pumping member provided valving is present in all three of the following locations; inlet valve means to the first chamber, valve means to control the flow from one face to the other (e.g., valved piston) and outlet valve means from the second chamber. It is not necessary that all of such valving be claimed, but all must be disclosed. In the absence of the disclosure of any of said valving in combination with the unitary pumping member the patent is excluded from this definition. See subclasses 437+. However, this definition does include those pumps in which the fluid is successively acted upon by different faces of a unitary pumping member if the faces move in the same direction to effect the pumping action. In this case the valving for the three locations above noted is not required.

(2) Note. This definition excludes those pumps having a unitary pumping member which includes a plurality of spaced serially arranged self-acting valves which simultaneously control the pumped fluid to or from a common expansible chamber; this not being considered to be a plurality of pumping units. See subclass 459.

(3) Note. Multi-stage rotary pumps of the expansible or nonexpansible chamber type are generally classified in Classes 415 and 418. However, said pumps are included in this class in certain combinations such as when driven by a significantly claimed motor. Such rotary pumps will be included under this definition only if they include a plurality of rotors or runners which have or are capable of relative movement during operation.

(4) Note. Apparatus in which the pump fluid successively flows from a pump chamber and then through a motor working chamber to be expelled therefrom with exhausted motive fluid is excluded under this definition as constituting successive stages. See subclasses 377+.

(5) Note. Relatively movable pumping members which successively act upon the pumped fluid are included under this definition and do not require the disclosure of valves in the three locations as set forth in (1) Note above.