Gravitational flow system for the sequential administration of medical liquids

Claim 1

A combined air barrier and liquid sequencing valve for the sequential administration of a primary liquid and a secondary liquid comprising: a housing divided into three or more chambers by a plurality of partition members; one of said partition members being disposed substantially horizontally within said housing so as to divide said housing into first and second chambers and to seal said first chamber from said second chamber; said first chamber in said housing having an inlet port incorporated therein for the passage of primary liquid into said first chamber, and an outlet port incorporated therein for the passage of said primary liquid from said first chamber into the second chamber, said outlet port from said first chamber including a hydrophilic membrane incorporated therein and covered thereby for the prevention of air movement between said first chamber and said second chamber when said hydrophilic membrane is moistened; an inlet port to said second chamber for the admission of secondary liquid and a plurality of outlet ports from said second chamber for the passage of primary and secondary liquid; and an air capturing pocket proximate said hydrophilic membrane covering said outlet port from said first chamber to said second chamber, said air capturing pocket being constructed and arranged for the reception of residual air within said second chamber proixmate said hydrophilic membrane when said secondary liquid is dispensed into said second chamber whereby the flow of said primary liquid is interrupted for so long as the pressure of said secondary liquid is greater than that of said primary liquid; said air capturing pocket being defined as the area below said outlet port from said first chamber to said second chamber, enclosed on one side by a third chamber extending at least partially downward below said horizontal partition, said third chamber having an inlet port from said second chamber incorporated at its base and sealed by a hydrophilic membrane whereby air may be entrapped below said outlet between said first and second chambers during dispensing of said primary liquid, said third chamber further having an outlet port positioned above said inlet port and opening out of said housing whereby secondary liquid may pass upwardly through said inlet port into said third chamber and out of said outlet port during dispensing of said secondary liquid.