Reagent-dispensing system and method

Claim 3

A method as recited in claim 1 wherein said pressure reducing step comprises coupling the exterior surface of said deformable pumping chamber to the atmosphere.

Claim 4

A method as recited in claim 1 wherein said pressure reducing step comprises coupling the exterior surface of said deformable pumping chamber to a vacuum source.

Claim 5

A method as recited in claim 1 and further including the step of thereafter reapplying a positive pressure to the exterior surface of said refilled deformable pumping chamber for initiating a further dispensing cycle.

Claim 6

Apparatus for dispensing metered amounts of a liquid comprising: liquid storage means for storing a liquid; means for defining a deformable pumping chamber, said pumping chamber containing a supply of said liquid to be dispensed; first couping means for coupling said liquid storage means to said pumping chamber; dispenser means for dispensing liquid from said pumping chamber; second coupling means for coupling said pumping chamber to said dispenser means, said second coupling means including first valve means having a valve closed position for blocking the flow of liquid from said pumping chamber to said dispenser means, and a valve open position for permitting the flow of liquid from said pumping chamber to said dispenser means; means for defining a pressure chamber adjacent to at least a portion of said deformable pumping chamber; a positive pressure source for pressurizing said pressure chamber; a source of reduced pressure for reducing the pressure in said pressure chamber; means for placing said first valve means in said valve closed position and for connecting said positive pressure source to said pressure chamber for pressurizing said pressure chamber while said first valve means is in said valve closed position for applying pressure against said means for defining said deformable pumping chamber; means for actuating said first valve means to said valve open position for a predetermined period of time while maintaining said pressure chamber pressurized, said pressure in said pressure chamber compressing said pumping chamber to dispense a metered amount of liquid from said pumping chamber to said dispenser means through said second coupling means; and means for connecting said source of reduced pressure to said pressure chamber for reducing the pressure in said pressure chamber, said reduced pressure allowing said pumping chamber to expand, the resulting reduced pressure in said pumping chamber causing liquid to be withdrawn from said liquid storage means into said pumping chamber through said first coupling means for refilling said pumping chamber with said liquid.

Claim 7

Apparatus for dispensing metered amounts of a liquid comprising: liquid storage means for storing a liquid; means for defining a deformable pumping chamber, said pumping chamber containing a supply of said liquid to be dispensed; first couping means for coupling said liquid storage means to said pumping chamber; dispenser means for dispensing liquid from said pumping chamber; second coupling means for coupling said pumping chamber to said dispenser means, said second coupling means including first valve means having a valve closed position for blocking the flow of liquid from said pumping chamber to said dispenser means, and a valve open position for permitting the flow of liquid from said pumping chamber to said dispenser means; means for defining a pressure chamber adjacent to at least a portion of said deformable pumping chamber; a positive pressure source for pressurizing said pressure chamber; a source of reduced pressure for reducing the pressure in said pressure chamber; means for placing said first valve means in said valve closed position and for connecting said positive pressure source to said pressure chamber for pressurizing said pressure chamber while said first valve means is in said valve closed position for applying pressure against said means for defining said deformable pumping chamber; means for actuating said first valve means to said valve open position for a predetermined period of time while maintaining said pressure chamber pressurized, said pressure in said pressure chamber compressing said pumping chamber to dispense a metered amount of liquid from said pumping chamber to said dispenser means through said second coupling means; and means for connecting said source of reduced pressure to said pressure chamber for reducing the pressure in said pressure chamber, said reduced pressure allowing said pumping chamber to expand, the resulting reduced pressure in said pumping chamber causing liquid to be withdrawn from said liquid storage means into said pumping chamber through said first coupling means for refilling said pumping chamber with said liquid.

Claim 8

Apparatus as recited in claim 5 wherein said source of reduced pressure comprises the atmosphere.

Claim 9

Apparatus as recited in claim 5 wherein said source of reduced pressure comprises a vacuum source.

Claim 10

Apparatus as recited in claim 5 wherein said positive pressure source comprises a 15 p.s.i. pressure source.

Claim 11

Apparatus as recited in claim 5 wherein said liquid comprises a chemical reagent to be dispensed in a chemistry analyzing system.

Claim 12

Apparatus as recited in claim 5 wherein said first coupling means includes one-way valve means for permitting liquid flow from said liquid storage means to said pumping chamber while preventing liquid flow into said liquid storage means from said pumping chamber.

Claim 13

Apparatus as recited in claim 10 wherein the liquid in said liquid storage means is exposed to atmospheric pressure.

Claim 14

Apparatus as recited in claim 5 wherein said means for connecting said positive pressure source to said pressure chamber and said means for connecting said source of reduced pressure to said pressure chamber comprises second valve means coupling said pressure chamber to said positive pressure source and to said source of reduced pressure.

Claim 15

Apparatus as recited in claim 12 wherein said second valve means comprises a three-way valve having a first position coupling said pressure chamber to said positive pressure source, a second position coupling said pressure chamber to said source of reduced pressure, and a third closed position.