Contamination-resistant dispensing and metering drop forming device
First Claim
1. A device for dispensing liquids in drop form of substantially uniform size which comprises a container having a dropper tip including a passageway for ingress of air to and egress of liquid from said device, said passageway communicating between the container and an orifice in the dropper tip;
- means for temporarily reducing the volume of the container; and
disposed within the dropper tip, across the passageway, a microporous composite membrane with pores of a size to resist passage of contaminants, said membrane having a liquophilic component permitting delivery of drops of a liquid to a desired location outside the container and a liquophobic component adapted to resist the passage of such liquid but to permit the passage therethrough of air, the surface area and pore size of said liquophilic component being so selected as to meter liquid being dispensed in drop form and avoid a stream of liquid from emerging from the dropper tip during normal use, said passageway being intersected by said membrane and communicating with both the liquophilic and liquophobic components.
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Accused Products
Abstract
A device for dispensing liquids in drop form of substantially uniform size is provided which includes a container having a dropper tip including a passageway for ingress of air to and egress of liquid from the device, the passageway communicating between the container and an orifice in the dropper tip; means for temporarily reducing the volume of the container; and, disposed within the dropper tip, across the passageway, a microporous composite membrane with pores of a size to resist passage of contaminants. The membrane has a liquophilic component which permits delivery of drops of a liquid to a desired location outside the container and a liquophobic component which is adapted to resist the passage of such liquid but to permit the passage therethrough of air. Both the liquophilic and liquophobic components of the membrane (which intersects the passageway) communicate with the passageway. The surface area and pore size of the liquophilic component is so selected as to meter liquid being dispensed in drop form and avoid a stream of liquid from emerging from the dropper tip during normal use.
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Citations
25 Claims
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1. A device for dispensing liquids in drop form of substantially uniform size which comprises a container having a dropper tip including a passageway for ingress of air to and egress of liquid from said device, said passageway communicating between the container and an orifice in the dropper tip;
- means for temporarily reducing the volume of the container; and
disposed within the dropper tip, across the passageway, a microporous composite membrane with pores of a size to resist passage of contaminants, said membrane having a liquophilic component permitting delivery of drops of a liquid to a desired location outside the container and a liquophobic component adapted to resist the passage of such liquid but to permit the passage therethrough of air, the surface area and pore size of said liquophilic component being so selected as to meter liquid being dispensed in drop form and avoid a stream of liquid from emerging from the dropper tip during normal use, said passageway being intersected by said membrane and communicating with both the liquophilic and liquophobic components. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 20)
- means for temporarily reducing the volume of the container; and
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19. A device according to claim wherein each of the liquophilic and liquiphobic components comprise polyvinylidene fluoride membranes.
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21. A device for dispensing liquids in drop form of substantially uniform size which comprises an elastically deformable container having a dropper tip with a passageway therethrough for ingress of air to and egress of liquid from said device, said passageway terminating in an orifice and, disposed within the dropper tip and across the passageway, a composite microporous membrane with pore sizes less than 0.45 μ
- m, said membrane comprising a hydrophilic component and a hydrophobic component, said hydrophilic component providing from about 60 to about 70% of the surface area of the composite membrane, said hydrophilic component having a surface area so selected as to meter liquid being dispensed in drop form and avoid a stream of liquid from emerging from the dropper tip during normal use, and said passageway being intersected by said membrane and communicating with both of said hydrophilic and hydrophobic components.
- View Dependent Claims (22, 23)
- 24. A device for dispensing liquids in drop form of substantially uniform size which comprises a container having a dropper tip including a passageway for ingress of air to and egress of liquid from said device, said passageway communicating between the container and an orifice in the dropper tip and, disposed within the dropper tip across the passageway, a microporous membrane with pores of a size to resist passage of contaminants, said membrane having a liquophilic component permitting delivery of drops of a liquid to a desired location outside the container, and a liquophobic component adapted to resist the passage of such liquid but to permit the passage therethrough of air, said passageway being intersected by said membrane and communicating with both of said liquophilic and liquophobic components, the surface area and pore size of the liquophilic component being selected so as to meter the liquid being dispensed in drop form and avoid a stream of liquid from emerging from the dropper tip during normal use.
Specification