Methods and apparatus for obtaining wider sprays when spraying liquids by airless techniques
AssigneeUnion Carbide Chemicals & Plastics Technology Corporation
InventorKenneth A. Nielsen
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Abstract
The present invention is directed to methods and apparatus for spraying liquid compositions by airless spray techniques so as to obtain wider spray patterns without having to alter the construction or configuration of conventional nozzles, nozzle tips or spray guns. By means of the present invention, the width of a spray pattern may be changed while the spraying operation is being conducted.
Claims44
In a method for the airless spraying of a coating composition which comprises passing the composition under pressure through an orifice to produce a spray pattern having a maximum first width, the said composition comprising (i) a solids fraction containing at least one component capable of forming a coating on a substrate;
- and (ii) a solvent fraction which is at least partially miscible with the solids fraction, the improvement which comprises forming a liquid mixture in a closed system, which liquid mixture contains the said (i) and (ii), and also contains (iii) at least one supercritical fluid in at least an amount which when added to (i) and (ii) and sprayed is sufficient to produce a spray pattern having a second width which is greater than the first width.
A method of increasing the spray width of an airless sprayed coating composition which is capable of forming a coating on a substrate which comprises admixing at least one supercritical fluid with the coating composition prior to spraying the resulting liquid mixture under pressure through an orifice, wherein the amount of supercritical fluid admixed is sufficient to increase the spray width.
A method of varying the spray width of an airless sprayed coating composition as it is being sprayed by admixing at least one supercritical fluid with the coating composition prior to spraying the resulting liquid mixture under pressure through an orifice and varying the concentration of the supercritical fluid admixed with the coating composition, wherein the amount of supercritical fluid admixed is sufficient to vary the spray width.
Dependencies are inferred from the claim text.