Metering dispensing system with improved valving to prevent accidental dispensing of liquid therefrom
A liquid dispensing device includes a storage container and dome pump mechanism attached thereto for metered dispensing. A one-way valve is employed to pull liquid from the storage container into the dome for metering. An exit passageway serves as an output valve. Each time the dome pump housing is depressed, a substantially equal volume of fluid is dispensed from the container. To prevent accidental dispensing, the one-way valve in the dome pump remains normally open and unsealed to allow backflow of liquid back into the storage container pouch when pressure is placed on the dome. The user squeezes the dome and base plate together to seal the one-way valve to urge liquid out through the exit port for actual dispensing. Also, interior pouch force creates backflow through the exit port back into the containment chamber to further prevent leakage.
1. A dispensing device, comprising:
a base plate, having an upstream side and a downstream side, and defining a liquid flow aperture therethrough;
a flap of material removably positionable over the liquid flow aperture and in sealing engagement with the downstream side of the base plate;
a flexible pump housing, having an inner cavity and a flap contact surface on an inner wall, sealed to the downstream side of the base plate and positioned about the flap of material; the flexible pump housing and base plate further defining an exit port;
the flexible pump housing being configured to draw liquid from the upstream side of the base plate, through the liquid flow aperture and into the inner flow cavity;
the flexible pump housing being further configured to urge liquid through the exit port when the flap contact surface of the flexible pump housing has pressed the flap of material against the downstream side of the base plate to seal the liquid flow aperture to prevent flow of liquid therethrough.
2. The dispensing device of claim 1 , wherein the base plate is of a convex configuration facing upstream; the base plate being deformable to a concave configuration upon exerting pressure on the upstream side of the base plate.
3. The dispensing device of claim 1 , further comprising:
at least one housing stand-off leg positioned on the flap contact surface.
4. The dispensing device of claim 1 , further comprising:
at least one base plate stand-off leg positioned on the upstream side of the base plate.
5. The dispensing device of claim 1 , further comprising:
an output valve positioned in fluid communication with the exit port.
6. The dispensing device of claim 1 , further comprising:
a storage container in fluid communication with the liquid flow aperture.
7. A method of pumping liquid, comprising the steps of:
providing a base plate, having an upstream side and a downstream side, and defining a liquid flow aperture therethrough;
removably positioning and sealing a flap of material over the liquid flow aperture with the downstream side of the base plate;
sealingly connecting a flexible pump housing, having an inner cavity and a flap contact surface on an inner wall, to the downstream side of the base plate and about the flap of material;
providing an exit port between the flexible pump housing and the base plate; drawing liquid from the upstream side of the base plate, through the liquid flow aperture and into the inner cavity;
sealing the liquid flow aperture by depressing the flexible pump housing to move the flap contact surface to press the flap of material against the downstream side of the base plate; and
urging flow of liquid through the exit port by further pressing the flexible pump housing.
8. The method of pumping liquid of claim 7 , further comprising the steps of:
providing a base plate of a convex configuration facing upstream;
deforming the base plate to a concave configuration upon pressing by exerting pressure on the upstream side of the base plate.
9. The method of pumping liquid of claim 7 , further comprising the steps of:
providing at least one housing stand-off leg positioned on the flap contact surface;
urging the at least one housing stand-off leg into the flap of material to seal it to the base plate and about the liquid flow aperture.
10. The method of pumping liquid of claim 7 , further comprising the steps of:
providing at least one base plate stand-off leg positioned on the upstream side of the base plate; pressing against the at least one base plate stand-off leg to urge the base plate from a convex to concave configuration.
11. The method of pumping liquid of claim 7 , further comprising the step of:
positioning an output valve in fluid communication with the exit port.
12. The dispensing device of claim 7 , further comprising the step of:
providing a storage container in fluid communication with the liquid flow aperture;
pulling liquid from the storage container through the liquid flow aperture and into the inner cavity of the flexible pump housing.
13. A dispensing device, comprising:
a container maintaining a material to be dispensed;
a dome pump received by said container, said dome pump having an inlet in communication with an interior of said container, and an outlet in communication with an exterior of said container;
a first valve interposed between said inlet and said interior of said container; and
wherein activating forces applied concurrently to opposite sides of said dome pump activate said first valve to cause passage of material from said dome pump and through said outlet, and activating forces applied to only one side of said dome pump activate said first valve to cause passage of material from said dome pump into said container through said inlet.
14. The dispensing device of claim 13 , wherein said first valve comprises a base plate having an aperture therethrough, and a flap of material selectively positionable over said aperture.
15. The dispensing device of claim 14 , wherein said flap of material is selectively positioned by said activating forces.
16. The dispensing device of claim 15 , wherein said base plate is of a normally concave configuration away from said flap.
17. The dispensing device of claim 13 , wherein said container is a pouch.
18. The dispensing device of claim 17 , further comprising:
a second valve interposed between said outlet and said exterior of said pouch.