Highly pressurized, purified liquid carbon dioxide is required for a variety of industrial processes. Such highly pressurized liquid is produced by purifying industrial grade liquid carbon dioxide that is available at about 13 to 23 bar (1.3 to 2.3 MPa) and then pumping the liquid to a pressure of anywhere from between about 20 and about 68 bar (2 to 6.8 MPa). The problem with pumping, however, is that impurities such as particulates or hydrocarbons can be introduced into the product stream as a byproduct of mechanical pump operation.
U.S. Pat. No. 6,327,872, incorporated by reference herein, and assigned to The BOC Group, Inc., the assignee of the present application, is directed to a method and apparatus for producing a pressurized high purity liquid carbon dioxide stream in which a feed stream composed of carbon dioxide vapor is purified within a purifying filter and then condensed within a condenser. The resulting liquid is then alternately introduced and dispensed from two first and second pressure accumulation chambers on a continuous basis, in which one of the first and second pressure accumulation chambers acts in a dispensing role while the other is being filled.
High purity CO2 can be used for the cleaning of optical components using the solvation and momentum transfer effects of CO2 when sprayed onto the optics. These benefits are achieved only if the purity of the CO2 is very high and the CO2 is delivered at a high pressure.
USPTO Backgrounds
USPTO Backgrounds