Gas separation: processes – With control responsive to sensed condition – Concentration sensed
Reexamination Certificate
2002-05-22
2004-05-25
Smith, Duane (Department: 1724)
Gas separation: processes
With control responsive to sensed condition
Concentration sensed
C095S241000, C096S156000, C096S157000, C137S015050, C264S001100
Reexamination Certificate
active
06740139
ABSTRACT:
The present invention provides a system useful for transporting and deoxygenating a solution. This system is useful for a manufacture involving transportation and deoxygenation of a solution.
BACKGROUND
In recent years, a wide variety of research has been carried out to develop polymeric materials useful for making extended-wear contact lenses which affect minimally corneal health and give wearers maximal comfort. Ideally, extended-wear contact lenses would display high oxygen permeability, high ion permeability, good wettability, adequate on-eye movement, and tear exchange ability, all of which are required to maintain corneal health and wear comfort.
There have been many attempts to blend different polymers having different properties to make extended-wear lenses having some of the above-mentioned desired properties. For example, U.S. Pat. No. 5,849,811 teaches a process and polymer composition for making extended-wear lenses. The extended-wear lenses, made according to the methods disclosed in U.S. Pat. No. 5,849,811, can have a balance of oxygen permeability and ion or water permeability, with the ion or water permeability being sufficient to provide good on-eye movement, such that a good tear exchange occurs between the lens and the eye. U.S. Pat. No. 5,849,811 discloses that the ion and/or water permeability of lens materials may be increased by initiating and completing polymerization in an atmosphere which is substantially free of oxygen. Deoxygenating a polymer composition (formulation) and transporting the deoxygenated polymer composition (formulation) may be required in manufacture of such extended-wear lenses before making extended-wear lenses by molding.
Therefore, there is a need for a system and method for deoxygenating formulations and transporting deoxygenated formulations in an industrial setting for manufacturing contact lenses. Such system and method preferably can be adapted to automated practices and perform with consistency.
SUMMARY OF THE INVENTION
The object of the invention is to develop an automated system capable of deoxygenating the formulation, transporting the deoxygenated formulation, monitoring continuously the oxygen content in the formulation, maintaining the oxygen content in the formulation at a low level, and dispensing formulation into molds.
An embodiment of the invention is an automated system for transporting and deoxygenating a solution. The system is designed to: 1) transport a solution through a deoxygenating device; 2) continuously monitor the oxygen concentration of the deoxygenated solution; 3) fill the solution in a reservoir and automatically maintain solution level; 4) automatically dispense the solution as requested; and 5) perform automatically solution preparation, and start-up and shutdown operations.
The system of the invention comprising: a deoxygenating means, a pumping means, an oxygen analyzer, a solution collection system, a solution dispensing system, and a computer system, wherein the computer system: a) controls the pumping means to pump the solution from the container through the deoxygenating means in which oxygen is purged from the solution and through the oxygen analyzer which monitors oxygen concentration in the system and provides a feedback to the computer system to adjust operations of the system to ensure that the solution is properly deoxygenated; b) controls the deoxygenating means to deoxygenate the solution; c) controls the pump means to fill the solution collection system with the solution; and d) controls the solution dispensing system to drain the solution from the solution collection system and to dispense into each of one or more receivers a prescribed amount of the deoxygenated solution from the solution collection system.
Another embodiment of the invention is a method for displacing oxygen trapped in a solution collection reservoir of a system of the invention, comprising displacing oxygen with a deoxygenated first solvent which is miscible with a second solvent used in the solution.
A further embodiment of the invention is a method for deoxygenating and transporting a solution. The method comprises: displacing oxygen trapped in the above described system of the invention with a deoxygenated first solvent which is miscible with a second solvent used for preparing the solution; draining the deoxygenated first solvent from the solution collection system; replacing the deoxygenated first solvent in the system with the solution that is deoxygenated; and dispensing into each of one or more receivers a prescribed amount of the deoxygenated solution.
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European Search Report.
Donlon Robert
Russell Todd Aldridge
Sidlo Milos
Gorman Robert
Meece R. Scott
Novartis AG
Smith Duane
Theisen Douglas
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